text: Use of substitutive nomenclature is recommended for group 13–16 main group organometallic compounds. Examples are:
  *AlHMe named methylalumane
  *BiIPh named diiodo(phenyl)bismuthane
  For organometallic compounds of groups 1–2 can use additive (indicating a molecular aggregate) or compositional naming. Examples are:
  * [BeEtH] named ethylhydridoberyllium or ethanidohydridoberyllium
  * [Mg(η-CH)] named bis(η-cyclopentadienyl)magnesium, or bis(η-cyclopentadienido)magnesium
  * Na(CHCH) sodium ethenide (compositional name)
  However the recommendation notes that future nomenclature projects will be addressing these compounds.